HIRANUMA APPLICATION DATA

Automatic Titrator

Date No.

B2

Sep. 12,2018

Determination of sodium acetatewith perchloric acid titration

Drugs andMedicines
1. Abstract

Sodium acetate is widely used in chemical and medical industry (E.g. Buffer, Antifreezing agent,
Alkalizing supplements, Dye chemical, Hydragogue). Determination method of sodium acetate is described onJapanese Pharmacopoeia and Japanese Industrial Standard (JIS K8371). Both methods employ perchloric acid
titration method, dissolve the sample in glacial acetic acid and titrate with perchloric acid – acetic acid standardsolution. Endpoint is detected by potentiometric titration with glass / reference electrodes.
CH3COONa＋

HClO4

→

CH3COOH＋

NaClO4

2. Configuration of instruments and Reagents(1) Instruments
Main unit: Hiranuma Automatic Titrator COM Series

Electrode: Glass electrodeGE-101B

Reference electrodeRE-201Z(Inner solution should be changed; it is described below)(2) Reagents
Titrant: 0.1 mol/L perchloric acid in glacial acetic acid standard solution

Titration solvent: Glacial acetic acidElectrolyte: Saturated sodium perchlorate in glacial acetic acid
(For inner solution of reference electrode)

3. Measurement procedure(1) Take 0.2 g of the sample into a 100 mL tall-beaker and accurately weigh it.
(2) Add 50 mL of acetic acid and dissolve the sample.
(3) Immerse the electrodes and start titration with 0.1 mol/L perchloric acid in glacial acetic acid standard
solution. Perform blank test without sample.

4. Measurement Conditions and Results
Example of titration condition
Measurement of blank
Cndt No.

1Method

AutoConstantNo.

11Size0Amp No.

1BlankD. UnitmVMolarity

S-Timer60

secFactorC.P. mL

0mL

T Timer

0sec

D.P. mL0mL

End Sens

300

Over mL

0.1

Max.Vol.

1Buret No.

Mode No.

17g

Pre Int00mL

Del K

00.1mol/L

Del Sens

0mV

1.000

Int Time

5sec

K0

Int Sens

3mV

L0Brt Speed

2Pulse16UnitmL

mL

FormulaDmL

Digits3

Auto In Pram.

sec

Non

Measurement of sample
Cndt No.

2

MethodAutoConstantNo.

21Size0Amp No.

1BlankD. UnitmV

Molarity

S-Timer60

sec

Factor

C.P. mL0mL

D.P. mL0mL

End Sens

300

Over mL0.2

mL

Unit

Max.Vol.

40

mL

Formula(D-B)*K*F*M/(S*10)

Digits3Buret No.

Mode No.

8g

Pre Int

00.01

mLDel K50.1mol/L

Del Sens

0mV

1.000

Int Time

5sec

K

82.03

Int Sens

3mV

L

0Brt Speed

2Pulse40

sec%

Auto In Pram.

Non

Measurement results
Measurement of sample
Measurement of blank
Measurement

Size

Titrant

No.

(g)volume (mL)

1―

0.01

2―

0.01

Statisticalresult

Avg. (mL)

0.01

Measurement

Size

Titrant

ConcNo.

(g)volume (mL)(%)

10.2029

24.69099.77820.202124.55399.61730.201024.44099.701

Statisticalresult

Avg. (%)

99.70

SD (%)

0.0805

RSD (%)

0.08

Blank measurement

Sample measurement

Examples of titration curves

5. Note(1) Effect of water on perchloric acid titration
Water mixed in sample solution affects to the reaction system of perchloric acid titration because of theleveling effect, which results in a negative effect such as lowered quantitative performance or getting lesssensitivity around the end point. Therefore please take care not to mix water in sample solution. Referenceelectrode for non-aqueous titration should be prepared as described in the following item (2), because
water of KCl solution commonly used as inner solution for reference electrode could be mixed in samplesolution.
(2) Preparation of inner solution for reference electrodeThe inner solution of the reference electrode RE-201Z is filled with saturated KCl aqueous solution
normally. For this measurement, it is necessary to replace inner solution to saturated sodium perchlorate inacetic acid solution. Replacement procedure is described below.
i) Prepare the saturated solution of sodium perchlorate in glacial acetic acid with reagent grade of these.
ii) Discharge inner solution from reference electrode RE-201Z and wash inside it with water and thenacetic acid.
iii) Fill the prepared inner solution into reference electrode from the supply port.
iv) Cure the electrode for one day before use.
(3) Experiment temperature
Acetic acid used as a solvent for the titrant has a relatively large thermal expansion coefficient, and when
the temperature changes by 1 °C, the titrant causes a volume change of 0.1 %. For accurate measurement,
factor titration and sample measurement should be performed at the same room temperature as much aspossible.
Keywords：Sodium acetate, Perchloric acid titration, Nonaqueous titration, Neutralization titration,*Some measurement would not be possible depending on optional configuration of system.